NicoleRaleigh said:

Give anything pharmacological four weeks before you judge it, and give anything measured weekly a four-point rolling average before you call it a…

True, and it depends on a baseline nobody has stated. Without knowing where someone started, the same number can be an excellent result or a disappointing one.

NicoleRaleigh said:

Give anything pharmacological four weeks before you judge it, and give anything measured weekly a four-point rolling average before you call it a…

This is exactly what I could not find anywhere else.

Adding the clinical framing, because it changes how the question reads. The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either. Those three things can all be true at once, and most arguments here are two people holding different parts of that.

Dr.NutriCornell said:

The honest answer is that the effect is real, the magnitude is contested, and the individual variation is larger than either.

This is my experience too, for whatever a second data point is worth. Nothing to add that would improve it.

Closing the loop on my own question.

Update, and it is the boring outcome: nothing was wrong. The measurement I was reading had moved less than its own week-to-week variation, which somebody said upthread and I did not believe.